Hemodialysis has become the accepted therapy for "End Stage Renal Disease" (ESRD). Since the establishment of federal financing for all U.S. citizens, tens of thousands of terminal patients have been given a second chance to live by hospital and kidney center dialysis. Treatments average five hours in duration, and three times a week in frequency.
Public law changed the intent of the ESRD program in 1979 by directing that patients must be given the option of home-dialysis treatment. Emphasis on home dialysis promises to substantially reduce reimbursement costs by the federal agencies.
Hemodialysis equipment currently available is in general, large, heavy and not really suited for the home, much less for travel.
This invention relates to easily transported, compact and light weight equipment that sacrifices none of the reliability or efficiency of its larger counterparts. This equipment can be used with any commercially available dialyzer, whether "coil" or "flat plate" or "capillary". (The dialyzer is a semi-permeable membrane device that, together with other hemodialysis equipment, purifies the blood by osmotic differentials, and removes excess fluid by pressure differentials.)
Hemodialysis requires, first of all, a "proportioning" system which accurately dilutes the dialysate concentrates with water (usually 34:1), and homogeneously mixes the resulting solution. The "dialysate" module then heats and deaerates the solution, and controls the rate of flow to the dialyzer.
Hemodialysis systems employ a built-in conductivity meter to ensure accurate dilution of dialysate concentrate between critical limits. Conventional calibration is generally performed by comparing the reading of this instrument with an external instrument by passing the diluted dialysate concentrate through said external instrument (such as a laboratory asmometer). Another method is to employ a "check point" or "calibrate circuit" within the built-in conductivity meter, usually a resistor in the electronic circuit. These prior art calibration methods fail to afford complete reliability and patient safety because of inherent variables, including significant potential for human error.
This invention describes a novel, simplified compact system of accurate proportioning which eliminates the need for complex mechanisms and controls (often combinations of precision hydraulic piston pumps operated by water pressure), and for sophisticated electronic sensing and feed-back serve circuits.